Facial nerve neuromas presenting as acoustic tumors

Facial nerve tumors can present as masses in the internal auditory canal or cerebellopontine angle and may mimic an acoustic neuroma. These tumors can occur in any segment of the nerve from the brain stem to the neuromuscular junction. Prior to the advent of computed tomography and magnetic resonance imaging with gadolinium, facial nerve tumors were often difficult to diagnose. Even with these modalities it may be difficult to distinguish preoperatively between an acoustic neuroma and a facial schwannoma. Particular signs and symptoms associated with facial nerve tumors (in the spasms, and a facial tic. These symptoms, combined with modem radiologic studies, should allow for more accurate diagnosis, patient counseling, and treatment. This report presents a series of 32 facial nerve tumors diagnosed and treated at The Otology Group from 1975 to 1992. Of these lesions, 12 (38%) were thought to be acoustic neuromas. Eighteen tumors were correctly identified preoperatively as facial nerve tumors. Two facial nerve tumors were found incidentally.     

Trans-petrous surgery in acoustic neuroma. Value of preoperative audiovestibular and facial investigation in the risk evaluation of facial nerve function

Between 1987 and february 1994, 162 consecutive patients with acoustic neuroma were operated on by an otoneurosurgery team, using transpetrous approaches (89% translabyrinthine, 8% middle fossa and 3% retrosigmoid). The relationship between the clinical, audiometric and vestibulographic characteristics and the post-operative facial nerve function were evaluated. In acoustic neuromas with cerebello-pontine component inferior to 3 cm without central neurologic signs (ic: central controlateral auditory and/or ipsilateral vestibular pathway alteration), good post-operative facial nerve function was achieved in 80% of cases. In acoustic neuromas superior to 3 cm with alteration of the central vestibular and auditory pathways, a good result was obtained in only 30% of cases which correlated negatively with preoperative facial dysfunction. These results underline the value of preoperative facial and audiovestibular examinations in predicting the postoperative facial nerve function following surgery for acoustic neuroma.     

Unusual metastasis of hypernephroma in the maxillary sinus

OBJECTIVES: To determine the predictive value of intraoperative threshold stimulus for facial nerve outcome and the prevalence and prognostic value of persistent trains of activity and frequent spontaneous or mechanically induced contractions during acoustic neuroma surgery. STUDY DESIGN: Prospective recording and subsequent review of facial nerve activity. SETTING: Tertiary referral centre. PATIENTS AND METHODS: Consecutive patients undergoing acoustic neuroma surgery. Intraoperative facial nerve activity was digitised and stored on a personal computer for future analysis. Operative events were flagged. Recordings were available in 27 patients. MAIN OUTCOME MEASURES: Frequent mechanically induced contractions (< 20), prolonged trains of facial nerve activity (total time > 199 seconds), and facial nerve brainstem stimulus threshold were correlated with facial nerve outcome. RESULTS: A brainstem stimulus threshold > 0.1 mA was significantly associated with intermediate or poor facial nerve function (House-Brackmann grade > 2) on the sixth postoperative day, at 1 month and 6 months. Patients with normal or near-normal facial function on the first day and a threshold of > 0.1 mA were significantly more likely to develop a delayed facial nerve palsy. Frequent contractions were noted in 74% of patients and persistent train activity in 59%. Neither was predictive of facial nerve outcome. CONCLUSIONS: An elevated brainstem threshold is helpful in predicting delayed facial nerve palsy and suboptimal facial nerve outcome. Persistent train activity and frequent contractions, do not have major prognostic significance.     

Endoscope-assisted vestibular neurectomy

OBJECTIVE/HYPOTHESIS: In some instances endoscopes offer better visualization than the microscope and frequently allow less invasive surgery. This study was undertaken to determine whether endoscopy is safe and effective during neurectomy of the vestibular nerve. METHOD: Ten patients with intractable unilateral Meniere's disease underwent a retrosigmoid craniotomy for neurectomy of the vestibular nerve. Endoscopy with a Hopkins telescope was used during each procedure to study posterior fossa anatomic relationships and to assist the neurectomy. Preoperative and postoperative audiometric evaluation was performed in all patients undergoing vestibular neurectomy. Nine of these patients had preoperative electronystagmography, and four patients completed postoperative electronystagmography. The 1995 American Academy of Otolaryngology-Head and Neck Surgery's Committee on Hearing and Equilibrium guidelines for the diagnosis and evaluation of therapy in Meniere's disease were used. RESULTS: Complete neurectomy was achieved in all 10 patients. Endoscopy allowed improved identification of the nervus intermedius and the facial, cochlear, and vestibular nerves and adjacent neurovascular relationships without the need for significant retraction of the cerebellum or brainstem. In addition, endoscopic identification of the cleavage plane between the cochlear and vestibular nerves medial to or within the internal auditory canal (n = 3) was not made with the 0-degree endoscope; however, identification was made with the 30- or 70-degree endoscope in all cases. In all patients with Meniere's disease, elimination of the recurrent episodes of vertigo (n = 10) or otolithic crisis of Tumarkin (n = 1) was achieved. CONCLUSIONS: Posterior fossa endoscopy can be performed safely. Endoscope-assisted neurectomy of the vestibular nerve may offer some advantages over standard microsurgery including increased visualization, more complete neurectomy, minimal cerebellar retraction, and a lowered risk of cerebrospinal fluid leakage.     

Intraoperative facial nerve monitoring in acoustic neuroma surgery

Intraoperative facial nerve monitoring simultaneously using electromyography and mechanical pressure sensors is being used in retrosigmoid and translabyrinthine approaches for acoustic neuroma resection. Insulated electrified microsurgical instruments and air drills are used to stimulate the facial nerve with a pulsed, constant current through bone and tumor, before the facial nerve is visually encountered. Electrical stimulation is used to help locate the facial nerve, map the course of the facial nerve within tumor, warn the surgeon of unexpected facial nerve locations, and help predict facial nerve function postoperatively. In 57 unmonitored cases a House-Brackmann (H-B) grade I or II result was obtained in 77 percent of small, 81 percent of medium, and 60 percent of large tumors. In 64 monitored cases H-B grade I or II was obtained in 88 percent of small, 79 percent of medium, and 90 percent of large tumors. Overall, facial nerve outcomes were better after monitored procedures (p < 0.02). A modified H-B classification for acute facial nerve injury is introduced to grade facial weakness immediately postoperatively and until function is stable at 1 year. In the unmonitored group there were five (9%) cases with a complete facial paralysis, facial nerve intact (i.e., acute H-B grade VIA) and seven (13%) cases with the facial nerve transected (i.e., acute H-B grade VIB). In the monitored group there were five (8%) acute H-B grade VIA and two (3%) acute H-B grade VIB results. In the unmonitored group of large tumors, there were statistically more patients with an acute H-B grade VIB result (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Rerouting of the intratemporal facial nerve: an analysis of the literature

Anterior rerouting of the intratemporal facial nerve in the infratemporal fossa approach is employed to access to the jugular bulb, hypotympanum, and lateral skull base, whereas posterior rerouting of the facial nerve, as employed in the transcochlear craniotomy, is most frequently used for surgery of the posterior fossa, cerebellopontine angle, prepontine region, and petrous apex. Facial nerve rerouting may lead to facial paresis or paralysis. This review of the literature is intended to define the physiologic "cost" of these procedures, so that the neurotologic surgeon can determine if the morbidity incurred in these techniques is worth the resultant exposure. Inconsistencies in reporting facial function places into question the validity of some of the cumulative data reported. Postoperatively, grades I-II facial nerve function was seen in 91% of patients undergoing short anterior rerouting, 74% of patients undergoing long anterior rerouting, and 26% of patients undergoing posterior complete rerouting. Although facial nerve rerouting allows unhindered exposure to previously inaccessible regions, it is achieved at the cost of facial nerve function. Facial nerve dysfunction increases with the length of facial nerve rerouted.     

Malpositioned endolymphatic subarachnoid shunt causing trigeminal neuralgia: case report

A case is presented of a 64-year-old female with a fifteen year history of right facial pain. The last nine years the facial pain is described as an intense, stabbing pain in the maxillary division of the right trigeminal nerve. The patient had Meniere's Disease for which an endolymphatic subarachnoid shunt was placed fifteen years prior. The patient underwent intensive medical and several surgical therapies for pain. Some of the procedures were initially successful but none provided lasting relief. Because of severe recurrent right facial pain, the patient underwent a right open partial rhizotomy of the trigeminal nerve via a retrosigmoid approach. Intraoperative findings included the end of the endolymphatic subarachnoid shunt in association with the trigeminal nerve roots. The end of the shunt was removed at the time of surgery. Postoperatively the patient has been pain free for thirty months. It is proposed a malpositioned or migrated endolymphatic subarachnoid shunt may be a cause of trigeminal neuralgia.     

Implementation of groups for creative expression on a psychiatric inpatient unit

Intracranial identification by electrostimulation and monitoring of the status of the facial nerve was intraoperatively used in 21 patients with cerebellopontine angle tumors of varying histological structure. Monopolar and bipolar electrostimulation, as well as electromyography and mechanography for recording the function of the facial nerve were compared. During removal of cerebellopontine angle tumors, identification and monitoring of the function of the facial nerve provide anatomic retention of this nerve when the tumor is radically eliminated. This is of essential significance for acoustic neurinomas. A combination of monopolar and bipolar stimulation for identification of the facial nerve simplifies removal of these tumors. As compared with electromyography, mechanography of facial nerve function during these operations is a more convenient technique due to the simplicity and absence of false operation for electric interferences. The study provided the optimum procedure for intracranial stimulation to identify the facial nerve within the cerebellopontine angle.     

Postnatal development of vascular beta-adrenoceptor-mediated responses and the increase in the adrenaline content of the adrenal gland have a parallel time course

Factors influencing facial nerve preservation and function in acoustic neuroma surgery were studied in 108 cases. Anatomic preservation of the nerve was inversely related to tumor size and improved as the series progressed. When the nerve was saved, normal postoperative function was inversely related to tumor size and was more common if the cochlear nerve was also saved. Most intact nerves eventually recovered some function, but late function was seldom completely normal unless there was some early recovery. The results demonstrate the importance of tumor size, operator experience, and ease of dissection on facial nerve outcome.     

Headache after acoustic neuroma excision

The retrosigmoid approach to acoustic neuroma removal has recently been criticized for causing frequent and severe headache postoperatively. We review 331 patients who had acoustic neuroma removal by the retrosigmoid approach at one institution. The incidence of postoperative headache was 23 percent at 3 months, 16 percent at 1 year, and 9 percent at 2 years. Management was primarily with analgesics, physiotherapy, and reassurance. No patient had additional surgical treatment. Information available indicates that the incidence of postoperative headache associated with the translabyrinthine approach is similar to that of the retrosigmoid approach. Perhaps filling the craniectomy defect will decrease further the incidence of headache postoperatively.     

Evaluation of quality of life and symptoms after translabyrinthine acoustic neuroma surgery

OBJECTIVE: This study aimed to describe the consequences of acoustic neuroma surgery in terms of symptoms and quality of life. STUDY DESIGN: This study was a retrospective case review. SETTING: The surgery was conducted in Uppsala, Sweden. PATIENTS: A consecutive sample of acoustic neuroma patients operated on between 1988 and 1994. INTERVENTION: All patients had been operated on with the translabyrinthine technique. MAIN OUTCOME MEASURES: A questionnaire was constructed including questions about the surgery and symptoms. The House and Brackmann scale was used for grading facial function and the Brackmann and Bars scale was used for self-assessment of facial function. RESULTS: Follow-up data were collected by a postal questionnaire sent out and returned by 141 patients, which yielded a 90% response rate. Normal to moderately impaired facial function (House I-III) was evident in 85.2% of patients, although residual facial problems were reported. Most considered hearing to be worse after surgery (80%), and tinnitus was found in 60% of the sample. Balance problems (45%), dizziness (19%), and headache/pain (22%) were also reported. Work ability was affected in 23%, and 37% reported a continued need for medical consultations, mainly because of facial problems and pain. Most (89%) were pleased with the preoperative information. CONCLUSIONS: This study showed that few patients with acoustic neuroma had experienced negative social consequences after surgery. Although not linked to the operation, residual symptoms were reported that may necessitate further rehabilitation.     

Startle responses measured in muscles innervated by facial and trigeminal nerves show common modulation.

Electromyographic (EMG) potentials of several head muscles were recorded simultaneously in freely moving rats with chronically implanted electrodes. The startle responses of m. temporalis, m. levator auris, and m. levator labii superior were compared. All muscles showed a parallel decrease in latency and an increase in response elicitability and amplitude with an increase in stimulus intensity. A significant latency difference of about 1 msec existed between m. levator auris and m. temporalis. The shortest latency of the EMG response in m. levator auris was 5.5 msec (110 dB SPL). A common fluctuation in response amplitude and latency was found in simultaneous recordings of muscles innervated by the facial and trigeminal nerve, respectively. This shows a common modulatory input to the startle pathway to the cranial motor nuclei. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impending paradoxical embolus: clinical imaging and successful surgical treatment

AIM OF THE STUDY: Postoperative sensory component of the facial nerve after acoustic tumor surgery has received little attention in the literature. The object of the present investigation was to review this specific topic analyzing the postoperative frequency of taste and lacrimation (crocodile tears or dry eye) abnormalities. MATERIAL AND METHODS: 54 patients who underwent acoustic tumor removal were selected for this study. Each of these patients was recalled and pre and postoperative evolution of the sensory dysfunction were assessed. The latters were correlated with the facial function evaluated according to the House-Brackmann classification. RESULTS: Postoperative taste dysfunction (reduced or changed sensation) was complained by 38.5% of the patients. After surgery, 42.3% of the cases had crocodile tears, while in 59.6% altered tearing occurred. DISCUSSION: The present study, according to the Irving et al's experience confirmed a significant incidence of postoperative abnormal function of the sensory facial nerve. The influence of the motor component on these outcomes was variable. Lacrimation worsened when facial function was poor. On the other hand, grades V or VI did rarely manifest crocodile tears. Clinically, these findings implies the importance of a preoperative counseling of such particular aspect in the candidates to surgery of acoustic neuroma in order to adequately motivate them and, at the same time, to reduce their psychological discomfort.     

Traumatic neuromas of the head and neck

An interesting case of a traumatic neuroma of the greater auricular nerve provides the impetus for a discussion of head and neck neuromas. Traumatic neuromas of the head and neck are relatively rare. Division of the greater auricular nerve during parotidectomy occasionally results in a traumatic neuroma. We report a case of a 73-year-old woman who presented with a traumatic neuroma nine years after undergoing superficial parotidectomy with dissection of the facial nerve for a mixed tumor. The patient had a 1.5 cm x 1.0 cm mass located below the old surgical site over the anteromedial border of the sternocleidomastoid muscle. The patient's past history was significant for Frey's syndrome, which is the result of abnormal neurologic growth. On first impression, the tumor was thought to be a recurrence of neoplastic disease; however, because of the evaluation, traumatic neuroma was suspected. An attempt at fine-needle aspiration of the mass was too painful to be carried out. At surgery, a whitish tumor was excised which, on final pathologic examination, revealed traumatic neuroma. The surgical literature is reviewed and the subject of head and neck neuromas, including their evaluation and management, is thoroughly discussed. Knowledge of this possible diagnosis may spare the patient and the surgeon needless worry, as well as unnecessary procedures, once tumor recurrence has been ruled out.     

CT and MRI features of cavernous haemangioma of internal auditory canal

A left internal auditory canal (IAC) cavernous haemangioma is reported in a 45-year-old Saudi male. The lesion was associated with rapidly deteriorating hearing loss and facial nerve dysfunction. CT showed a calcified enhanced IAC lesion while T1 weighted MRI showed an isointense contrast enhancing lesion bulging into the porus acousticus. The imaging features of the three usual IAC lesions--meningioma, acoustic neuroma and cavernous haemangioma--were compared. Calcification/ossification appear more commonly in cavernous haemangioma than in the other two lesions while facial nerve dysfunction is a clinical hallmark of IAC cavernous haemangioma.     

Fear of childbirth during pregnancy may increase the risk of emergency cesarean section

The clinical features of progression sensorineural hearing loss and vertigo in combination with the radiologic finding of a contrast-enhancing mass within the inner auditory canal are suggestive of an acoustic neuroma. We report our findings in a 57-year-old woman with known mixed connective tissue disease who was presumed to have a neuroma. A large malignant lymphoma of the cerebellopontine angle presented clinically with a primary acoustic none palsy and no other central neurological deficits. Both the primary radiological examinations and the exclusively peripheral nerve palsy failed to indicate manifestations of a lymphoma. The development of a progressive facial palsy within 8 weeks of presentation and an atypical occipital headache were uncommon findings for an acoustic neuroma. Such changes in symptoms despite the occurrence of cardinal symptoms require further diagnostic measures. Manifestations of a malignant lymphoma in the cerebellopontine angle are extremely rare. To our knowledge a case of an intracerebral lymphoma in a patient with Sj?gren's syndrome has never been reported before.     

Neural conduction velocity of the human auditory nerve: bipolar recordings from the exposed intracranial portion of the eighth nerve during vestibular nerve section

We measured the conduction velocity of the intracranial portion of the auditory nerve in 3 patients undergoing vestibular nerve section to treat Ménière's disease. The conduction velocity varied from patient to patient, with an average value of 15.1 m/sec. The latency of peak III of the brain-stem auditory evoked potentials (BAEPs) increased by an average of 0.5 msec as a result of exposure of the eighth nerve, and if that increase is assumed to affect the entire length of the auditory nerve (2.6 cm) evenly, then the corrected estimate of conduction velocity would be 22.0 m/sec. Estimates of conduction velocity based on the interpeak latencies of peaks I and II of the BAEP, assuming that peak II is generated by the mid-portion of the intracranial segment of the auditory nerve, yielded similar values of conduction velocities (about 20 m/sec).     

Intraoperative facial nerve monitoring (IFNM) predicts facial nerve outcome after resection of vestibular schwannoma

Intraoperative facial nerve monitoring (IFNM) is a suitable technique for intraoperative facial nerve identification and dissection, especially in large vestibular schwannomas (VS) (acoustic neuroma). To evaluate its feasibility for estimating functional nerve outcome after VS resection 60 patients underwent surgery using IFNM. Out of this group the last 40 patients were included in a prospective study evaluating the prognostic value of various IFNM parameters (proximal and distal absolute EMG amplitude, stimulation threshold, and proximal-to-distal amplitude ratio) for prediction of initial postoperative facial nerve function and recovery of function. Stimulation threshold and absolute EMG amplitude proximally at the brain stem were both predictive for postoperative nerve function. Good initial facial nerve outcome (modified House Brackmann grading, mHB degree I and degree II) was found in 15/16 patients with a proximal EMG amplitude greater than 800 microV and in 19/22 patients with proximal stimulation threshold less than 0.3 mA. Sixteen of 16 patients with proximal stimulation threshold equal to or greater than 0.3 mA had moderate-to-severe facial palsy (mHB degree III or worse). Six of six patients without evokable proximal amplitude initially had insufficient nerve function (mHB degree IV). Intraoperative decrease of the proximal amplitude was associated with an unfavourable outcome, whereas distal amplitudes usually stayed unchanged. Mean distal EMG amplitudes were also found to be decreased with poor nerve function, which may mean that the tumour had already affected the nerve. A proximal amplitude of 300 microV or less and a proximal-to-distal amplitude ratio below 1:3 were found in the absence of functional recovery in 6/8 (75%) and 5/6 (83%) patients with initial mHB degree IV, respectively. Two patients with initial mHB degree IV improved to mHB degree III despite intraoperative evidence of missing functional nerve integrity. Therefore, functional recovery cannot be predicted by IFNM in all cases of anatomical nerve preservation. We conclude that a minimum follow-up period of 1 year may still be advisable even in certain patients without evidence of intraoperative functional nerve integrity.     

Three types of reticular neurons involved in the spino-bulbo-spinal reflex of cats

Reticular neuron activity was recorded in 28 chloralosed cats in order to analyze the reflex arc of the spino-bulbo-spinal (SBS) reflex. Three types of reticular neurons, types I (input), II(output) and III (relay), were identified by unit discharges in response to stimulation of the sural nerve. (1) Type I (input) neurons received spinal ascending volleys monosynaptically and responded to stimulation of the sural nerve with spikes of low amplitude and short latency. Unit spikes, however, were not produced by stimulation of the superficial radial nerve and the sensorimotor cortex. These input neurons were located in the dorsocaudal part of the medial bulbar reticular formation. (2) Type II (output) neurons were part of the reticulospinal tract, which sends axons to the spinal cord, since these neurons exhibited antidromic spikes following stimulation of the ventrolateral funiculus of the spinal cord. Unit spikes were evoked by stimulation either to the sural or superficial radial nerves. These neurons were located in the ventrocaudal part of the medial bulbar reticular formation. (3) Type III neurons included relay neurons. Unit spikes were evoked by stimulation of the sural nerve, superficial radial nerve and sensorimotor cortex. However, unit discharges were not obtained by antidromic stimulation to the reticulospinal tract. These neurons were distributed widely in the brain stem, both in the bulb and pons. (4) Latency difference of unit discharges between input and output neurons was 3.5--5 msec, indicating the presence of interneurons (relays) between input and output neurons. Spikes of output neurons with 3.8--4.2 msec latency were observed following stimulation of the region where input neuron activity was found. We may conclude that three kinds of reticular neurons, input, relay and output, were involved in pathways of the SBS reflex.     

Massive hemorrhage of the digestive system secondary to ulcerated colonic malacoplakia

The presence of an earlier latency of 12 msec of a somato-sensory evoked potential elicited by the stimulation of the median nerve at the wrist was discovered in 1963 by Liberson and Kim. They suggested its origin in the cervical spine or in the brain stem and possibly the cerebellum. Liberson, Voris and Uematsu recorded directly these potentials from the cervical spine and from the mesencephalon during surgery for pain in 1969 and published some of the findings in 1970. Cracco and Bickford confirmed in 1968 the findings of Liberson and Kim.